+ Biologic Behavior
- CSA is a malignant cartilage-producing neoplasm arising de novo within bone
- CSA is the 2nd most common primary bone tumor (5%-10%), but uncommon in the appendicular skeleton
- CSA should be differentiated from chondroblastic OSA
- Etiology is unknown but can arise at multiple cartilaginous exostoses sites or previous bone lesion
- Median age 8.7 years
- Breed predisposition: Golden Retriever
- 61%-91% CSA occur in the axial skeleton (i.e., nasal cavity [26%-36%], ribs, pelvis, vertebrae, and skull)
- Other CSA sites include the appendicular skeleton (<20% data-preserve-html-node="true" to 26%), digits, os penis, and extraskeletal sites (i.e., mammary gland, heart valves, aorta, larynx, trachea, lung, and omentum)
- CSA is slow to metastasize
+ Staging
- CSA is classified as primary or secondary:
- Primary CSA: de novo tumor unassociated with preexisting lesion)
- Secondary CSA: tumor associated with preexisting cartilage lesion (i.e., osteochondroma or multiple cartilaginous exostoses)
- Central (i.e., medullary) and peripheral (i.e., periosteum) classification is only applicable to secondary CSA
+ treatment
- Surgical resection is the preferred treatment for cats and dogs with CSA
- Radiation therapy is recommended for unresectable lesions
- Chemotherapy is recommended for grade III CSA
- Ciprofloxacin, a fluoroquinolone with known toxicity to chondrocytes, inhibits chondrocytic proliferation and induces apoptosis in vitro and may be toxic to CSA cells
+ Prognosis
- Tumor location is prognostic with CSA in the skull, nasal turbinates, and appendicular skeleton having a better prognosis than rib CSA
- MST 210-580 days for dogs with nasal CSA and metastasis is very rare
- MST 1,080 days for dogs with rib CSA
- MST 201-540 days for dogs with appendicular CSA treated with limb amputation ± chemotherapy
- 12-month survival time 17% and 24-month survival time 13%
- Histologic grade: I, II, and III
- Histologic grade is an important prognostic indicator for CSA of the same site